Electric motor and controlling system.



P. B. RAE.

ELECTRIC MOTOR AND CONTROLLING SYSTEM.

APLIOATION FILED JUNE 25, 1907.

Patnted DecQ20,1910.

4 SHEETS-SHEET 1.

ymxzvs.

L mvemoR. FRANK B. W/ T .i i iqgfl l hl lmli l WITNESSES- T O A- F. B.RAE. ELECTRIC MOTOR AND GON TROLLING SYSTEM.

APPLIOATION FILED JUNE 25, 1907.

Patented 118x120, 1910.

4 BHEETB-BHEET 2.

o INVENTOR- FRANK B-RAE. a ATTORH Ys.

WITNESSES;

F. B. RAE. ELECTRIC MOTOR AND CONTROLLING SYSTEM.

APPLICATION FILED mums, 1907. I

979,094, Patented Dec.20,1910.

. 4 8HBETE-SHEET 3.

iHVEPITOR.

IHI l FRAHKBRAE.

( ATTORNEYS- P. Br RAE. ELEGTRIG MOTOR AND CONTROLLING SYSTEM.

APPLICATION FILED JUNE 25, 1907.

Patented Dec. 20, 1910.

HiVE NTORk WITNESSE5.

FRANK E5 RAE.

ATTORHT i1 UNITED STATES PA TENT OFFICE.

FRANK B. RAE, OF DETROIT, MICHIGAN, ASSIGNOR, BY MESNE ASSIGNMENTS, TORAE ELECTRIC COMPANY, A CORPORATION OF MICHIGAN.

ELECTRIC MOTOR AND CONTROLLING SYSTEM.

reference to electric motors of the Variable speed type such as are usedfor the operatlon of elevators, machine tools, vehicles, the inventionhas ref erence to motors which are to be operated under conditionsof'varying load and speed, wherein it is desired to economize, as far aspossible the starting current, and to prevent, by automatic means actingirrespective of the operator or the position of the controller anabnormal flow of current.

In motors propelled by current from a storage battery, such as are usedin automobiles and railway cars, the use of armature resistancesinvolves a large waste of.

current, which reduces the mileage which can be obtained from a singlecharge of the battery, and an object of this invention is to provide avariable speed motor in which. the speed changes are obtained by varyingthe field magnetization and the ohmic resistance of the field at thesame time. Preferably, I have rovided amotor having the field coilsdividb'cl into a. number of groups each having a different ohmioresistance, together with a controlling switch which successively cutsout one group of coils after another. Thus, at the starting position allof the groups are connected in series, to produce the maximumfieldmagnetization and giving a circuit of the largest ohmic resistance, andat successive positions the groups of coils of progressively diminishingresistance are cut out, until at the full speed running position, boththe field magnetization and the ohmic resistance of the circuit are atthe lowest value.

A further object of the invention is to provide in combination with avariable speed motor having a manually actuated controller, rentpermitted to flow in starting the win tor will be determined; accordingto the counter electromotive force developed by the motor andindependently of the position of Specification of Letters Patent.Application filed June 25,

Patented Dec. 20, 1910. 1907. Serial No. 380,733.

the controller handle. Under ordinary conditions, it is possible for theoperator to move the switch rapidly to its extreme position, therebyadmitting full currenh'to the motor before it has time to accelerate andproduce suflicient counter E. M. F. to hold. back the current. Toprevent this abnormal flow of current irrespective of the action of theoperator or the position of the controller,

I have provided a yielding actuating connection etween the controllerhandle and the moving contacts which regulate the motor connectlons 1ncombmation with a brale ing or retarding magnet connected in thearmature circuit and of such. proportions that, when a predeterminedamount of current is exceeded, acts to lock the moving contacts untilthe current flow is cut down by increase of counter E. M. F.sufliciel'ltly to release the moving contacts. In case the controllerhandle has been moved beyond a position corresponding to a certaincounter E. M. F. the magnet will, as above stated, lock the contacts atthe position correspond ing to that speed of the motor which, with acertain magnetization produces the predetermined current which energizesthe magnet, but when the magnet is released by the diminution of currentthe yielding actuating. connection automatically moves the contacts to aposition corresponding to the position of the controller handle, or to ameans whereby the amount of cur-' position where the magnet is againenergized to lock the contacts. By this means, the current isautomatically kept below the predetermined amount, which will of course,be calculated -for individual conditions. In operating an automobile forinstance, it is at times desirable to operate the motor under abnormallyheavy current, and to this end, means is provided whereby the automaticbraking means can be thrown-out of operation when desired.

The invention will be more fully eX- plained herein in' connection witha diagrammatic view showing the general operation of the invention, andthen in connection with a specific form construction for obtaining thegeneral reysults stated.

In the accompanying drawings, Figure l is a diagrammatic view of a motorembodying the invention; Fig. 2 is a front elevation of the controllingswitch; Fig. 3 a p an view,

of controlling switch embodying the preferred form of mechanicalEricpartly insection; and Fig. d an end e'levafour separate windings, inwhich the sizes of wire and number of turns are varied to produce thedesired excitation under vary ing conditions and positions of thecontroller switch. Each pole is provided with four windings F F F andFfl respectively, corresponding windings on each pole constitutinggroups. The coils F? are of relatively fine wire and many turns, thecoils F are of coarser wire and of less number of turns, the coils F areof-still coarser wire and fewer turns, and. the coils F areprojportioned for the maximum speed of the motor under full loadconditions. These coils are connected in series with the armature A, andare successively cutout by the controller until, at maximum speed onlythe coils F are in circuit, which is the maximum speed position. lVhilethe running positions are four in number, starting with all of the coilsin series, and ending with only the coils F in series, in order to avoidsudden in *CI'GHSQS in current in the coils between the runningposition, the coils F are themselves successively cut out in going fromthe first position to the second position, and from the second runningposition to the third running position the coils F are successively cutout, and likewise for the coils F in going from the third to the fourthrunning position.

In Fig. 1, at, 5,43, 7 and 8, are stationary contact fingers; lingers 5and (5 being terminals of the battery B, or other source of supply;finger d'being the terminal of coils .F*, and fingers '7 and Sbeing thearn'iature terminals. 9, 1.0 and ll. are movable contacts cooperatingwith these stationary fingers for forward positions, and 12, 13, 14k

- and 1 5 are movable contacts for the reverse direction. Moving withthe movable contacts S), 10, 11 is a movable contact 16 which isconnected with the actuating means for the contacts 9, 10, 11 by aspring 17, or otherwise as will be hereinafter explained. The contacts'16 engage with fixed contacts 20, 21, 22-,

of which contacts 20, 24, 2S and 32 are for running positions, and theremainder being transitory positions wherein the 'coils 'of each group Eetc., are successively cutout. \Vhen the contact 16 is on contact 20,all of the coils FQQF, F F are in series, from which the on uit returnsto contact 4, and thence by strip 9 and contact 5 to,the battery. Inmoving from contact 21 to 24:, the

coils of group F willbe successively cut out, so that when contact 2d isreached, "the current in the remaining coils will have the relativelyhigh resistance of COIlS F wasremoved.-

been gradually increased as Between coils z t-and 28', the samecondition the st rip 11 carried by the drum 4E2.

ed between the contact disk 43 and the in occurs with coils F exceptthat coils F are of coarser. wire than the coils F and of somewhat fewerturns, so that the resistance removed from the circuit of the motor isnot as great when the coils F wereremoved. Also in going from contacts28 to contacts the same resultoccurs with the coils F the resistanceremoved in this case being less than in the case of the" coils F thecoils F remaining, the total ohmic resistance of the motor is at thelowest point, and the coils F will be proportioned according to thespeed with the desired field magnetization. the operation of a switch ofthis ,design, it

would be possible for the operator to move I the switch rapidly to theextreme position, which would not give the motor time to acceleratesufficiently to produce a counter E. M. F. to hold back the current,thus causing an abnormal How of current tending to waste the storagebattery charge and also "to injure the battery itself. To prevent thisabnormal flow of current irrespective of the action of the operator orthe position of the controller, the actuating means for the contact 1Gis controllable by means of a magnet located in the armature or mainmotor circuit, in which the pull will vary with the armature current.This magnet is caused to operate suitable actuating means for thecontact. 16 to retard or lock the same wienever there is an abnormalcurrent flowing, and thereby preventing movement of the contact 16tending to increase the current flowing. To accomplish this, the contact16 is connected with the actuating shaft on which thi contacts 9, 10,ll, 12, l3, l4, and 15 are mounted in such manner as to be yieldinglymoved through the spring 17, and. the magnet 3.3 prevents the springfrom With and load of the motor, and, p

moving the contactwhenever an abnormal I current is flowing.

The specific construction of switch is shown in Figs. 2, 3 and et whichwill now be described. 40 is shaft rotating in bearings in a frame orcasing ll, and mounted on a drum +2 to rotate therewith are the contactstrips 9 to 15 inclusive, on which bear the fingers 4, 5, 6 7, 8 beforedescribed. Mounted at one end of the frame is an in su lating disk onwhich the contacts 20 to inclusive are mounted. The drum 42 also carriesa contact disk 43 connected to Mountsulating disk 45 carrying thecontacts 20 to 32 inclusive, is a drum 46 which is mounted on the shaft40" to rotate independently thereof. 7 Connected between the interior ofdrum d6 and the shaft 40 is the coil spring '17, so'that whenever theshaft is turned the i l p the staring,

the drum to a position on the drum and are pressed outwardly by a spring47, 4.8 being a flexible wire for carrying the current between disk 43and the contacts 20, etc. in order to turn thc shaft 40, a pinion 4t)and opera ting gear sector mounted on a shaft 51v arc providta'l theshaft 51 having suitable actuating connections to be Opttl'lltttl by thedriver of the vehicle. (Tart-led by the drum in is a gear wheel 53, andmeshing; with the gear Wheel 53 is a pinion 5t loosely carried by ashortshait 55 journalcd in the casing ell. It. will be seen thatif therotation ol" the drum to be iuu'ibstrncted. the contact 16 will movewhenever the shaft t0 is moved, and if the rotation of the drum 46 isobstructed the contact 10 will not"inove no matter how tar the shaft 40be turned such movement of the shaft 4h simply winding up or unwindinthe spring 17. In order to lock the drum 46, means provided forpreventing thc rotation of shaft .3 5 and controlled by the inagns-it 33heretofore mentioned. 'lne shaft 55 is mounted in a soft iron casing 56,and mounted on the shaft 55 is an arn'iature 5T rotating tl'ierewith.Screwed into the casing; 56 is a soft iron plug 58 which is held inadjusted position by a screw (57. Surrounding the plug 58 and Withincasing 56, is the magnetizing coil or magnet 33. before described, whichis connected in the main inotor circuit. It- Will be seen that if -acurrent circulating in this magnet 33 strong enough, the armature 57will be at traoted by the attract on of the polar proections andujiagnetically held against turnving across the intervening air gapbetween it and plug 58. If desired the armature could be movablelongitudinally of the shaft. and, when attracted, interlock with the ca.ing to prevent rotation of the shaft. Also it will be seen that the pullof the magnet can be adjusted by screwing the plug in or out. The loosepi .on is provided with clutch teeth 59, which are engaged by a slidingsleeve tit} spli'ned on the shaft 55. Whenever the armature 57 isattracted to the plug 58, the spring 61- will engage the sleeve (i0 withthe pinion 54, and b Y reason o-f the frictional engagement betweenarmatme and the face of plug 58 prevents the rotation of gear wheelMyandthereby of the drum The coil 33 is so proportioned thatwhenovcritcarries'the maximum current to be permitted under norinailconditions, it will attract the armature 57, and thus pro vent rotation"of the drum 46 carrying the contact us. The oi'Jci-a'tor may attempt. toturnthc shaft 4-0, but this will only-"wind or unwind it from its normalcondition, Without moving; the contact Whenever the current. docs fallso that the spring; 61' releases the armature 5'7. the tension of thespring will. automatically turn correspondingwith l l Il l the positionof theshal't 40. If, however, a. condition arises in which thepredetermined current is not sntiicient. to move the motor, it desirableto throw the auto.- matic device out of action. This is acconrplished bymeans of the magnet coil 33, which is controlled by a i The effect: ofenergizing this coil (3;? is to attract the sleeve armature (it) againstthe tension of spring 61. thereby releasing the clutch 59 and permittingthe drum to be revolved freely either by the operator or by theaccumulated tension of the coil spring 17. Also, under somecircuinstaaces, this same resultcould be secured by causing the pushbutton 64 to short circuit the to szfnet (i i.

In the diagram-matuview, Fig. 1. they magnet 33 is shown actuating alcve r (it; which acts on a brake-Wheel ti? on the shaft- 55, whileclutch 59 in Fig". l acts the same as clutch 59 in Fig. 3. beingcontrolled by a magnet (33. In Fig, l the spring 17 tends to pull thecontacts 16 over the stationarv contacts 20 to 32. It will be seen fromFig 1 that reversal is secured by means of the armature contacts 13,l-t, to in Fig. 1. with out reversing the field connections: 'lihereversed positions are the same as the forward positions :20, 2t. but itwill be obvious that as many reversingcontacts may be used as isdesired. it will be seen that. the first movement of the actuatingsl'iait 40 closes contacts 4, 5. t3. 7. ti on strips 9, it). it, therebyclosing" the circuit to the regulating contacts 20, ct. arr and thatfurther move inent of the actuating shaft does not change the relationsof the brushes 4, 5, 6, 7 in all cases it will be understood that. thecontrolling lever connected to the shaft it usually set to a certainspeed position by the operator, he desires, and this prevents the spring1? from opening; the circuit the contacts 4, ct sci as would be. thecase unthe shaft 4.!) was held in some way.

thrown back toopen circuit position at any time, even though th sniagnet 33 has locked the contact 18 against ,inoveinent, and in casethe circuit is opened at the contacts 4, as soon as the current inmagnet drops the spring 17 will automatically return the contact 16 tostarting position or rather the first rui'ining' po.- ion at thecoiitact 20. Fro .i the foregoing description it thought that the natureand advantages of the invention will be fully understood. It will beseen. thatby this controlling mechanism described in which therelatively high resistance and strong magnetizing coils are out outfirst, in succession, that the motor will be gradiizally accelerated. Also itwill be seen that: the current will not be wasted in uselessresistances. besides 'ttartint the motor under a strong field, wl'iichis decontact. fi l, prefer ably controlled by a toot push button.

it I will also be seen that the shaft 40 can be sirable in motors usedfor vehicles and truetion. purposes. By i'nea-ns of the automaticwithout. depnrting from the scope of the invention.

Having'thus descriped my invention,What I'claim and desire to secure byLetters Patent, is:

l. The combination with a series motor having its field Winding composedof n plunlity of groups of coils, each group being composed of adiflerent number of turns having a predetermined ohmic resistance, of ncontrolling switch and connections whereby the coils forming each groupare successively cut out and the groups thus suc cessively andprogressively cut out to diminish the total ohmic resistrincc and magnetization and increase the current flow.

2. The combination with e motor proi ided with. a field winding composedoi a plurality of groups ot'coils proportioned to have a. maximumohi'nic resistance and magnetizing efl'ect when connected in series,

of acontrolling switch and connections.

whereby the coils forming each. group are successively cut out and thegroups thus progressively cut out to diminish the total ohmic resistanceand magnetizationend in crease the current flow.

I The combination with e series motor having its field Winding composedof n. plurality ofgroups of coils, each group being composed of a difi'ercnt nui'nber of turns wound to have each a predetcrmined ohmicresistance, of u controlling switch and con- Q nections whereby thegroups are successively and progressively cut out to diminish the 3total ohmic resistance and magnetization;

and increase the current flow.

4. In con'ihnmtion with a series motor having its held winding composedof a plui a l l coils are successively and progressively out out tosimultaneously. diminish the ohmic: resistance and magnetization andincrease the current. flow l In con'ibinetion with a storage battery,-of scricsmotor having its field Winding composed of a plurality ofgroups of coils conncctedin. series, .said coils comprising diil'cringnumbers of turns of predetermined ohmic resistances, and astartingswitch having connections with said groups of coils 'ii-herehy instarting the motor the current is maintained writhin definiteValues-While said. group of coils are successively and pro gressive'lycut out.

5. The combination with 2. storage battery, of a series motor l'iaiingits field Winding composed of plurality of grougiis of coils, each groupbeing. composed of i1- diiierent number of turns, and a controllingswitch having connections with said groups of coils whereby in operatingthe motor the current is maintained. within definite values.

7. The combii'iation with a storage battery, of a motor having its fieldWinding composed of a plurality of groups of coils conv nee-ted inseries said coils comprising diliering numbers of turns of diiierentresistances and a controlling switch having a i'ni'avnble switchclement, said controlling switch furthercolnprising it yieldingactuating conncciion for said. switch element, and means forliolding'sziid switch element against ac tnation by suid yielding;connectionwhen. the

current exceeds n predeternnncd ainoijint.

in testimmrv whereof E :il'lix my signature, in presence of twowitnesses.

FRANK B. RAE. l fitnesses:

Gisoncn Si Cnoss, V. J GiLnmr.

